What causes death in bladder cancer patients?

Heart diseases, chronic obstructive pulmonary disease (COPD), concomitant cancers, and other co-occurring diseases elevate the risk of death in patients with nonmuscular invasive bladder cancer (NMIBC), nonmetastatic muscle invasive bladder cancer (non-MMIBC), and metastatic bladder cancer (MBC), according to a recent study.

“Deaths caused by nonbladder cancer accounted for a considerable proportion of patients with bladder cancer,” the researchers said. “Our findings will help guide bladder cancer patients about their future health and life managements.”

Drawing from the National Cancer Institute’s Surveillance, Epidemiology, and End Results database, researchers identified 111,784 NMIBC, 26,546 non-MMIBC, and 4,678 MBC patients, all of whom had been diagnosed from 2004 to 2015. The main study outcome was cause of death, assessed according to diagnosis and other background factors.

In the NMIBC subgroup, 9,183 patients died of bladder cancer during the follow-up period, accounting for 20.57 percent of deaths in this patient population. Meanwhile, 18.07 percent of deaths were due to other malignancies (61.36 percent). [Am J Transl Res 2022;14:3494-3515]

Of note, NMIBC patients were at least 30 times more likely to die of bladder cancer than general-population controls (standardized mortality rate, 31.52, 95 percent confidence interval, 30.88–32.17). Other common malignant causes of death in NMIBC patients were lung and bronchial, pancreas, kidney and renal pelvis, and liver cancers. Noncancer causes of death included heart disease, COPD, diabetes mellitus, and nephrosis.

In the non-MMIBC subgroup, 18,829 patients died chiefly of bladder cancer (62.65 percent). Cancer-related causes of death were lung and bronchus, prostate, ureteral, stomach-related, and pancreatic cancers. As in NMIBC patients, nonmalignancy causes of death included cardiovascular disease, COPD and allied conditions, and diabetes mellitus, among others.

Meanwhile, malignant tumours were the main cause of death in patients with MBC, accounting for 91.85 percent of mortalities in this group. Indeed, the risks of dying from prostate, kidney, renal pelvis, and ureter-related cancers were significantly elevated in MBC than in non-MMIBC patients. Mortality from lung, colon, rectal, and liver cancers were all also higher than what was expected.

MBC patients had similar noncancer causes of death as non-MMIBC and NMIBC comparators, including COPD, cerebrovascular disease, and diseases of the heart. Infectious disease such as HIV and parasitic infections were also more likely to lead to death in MBC patients than in population controls.

“Studies have shown that cancer patients faced a higher risk of death from cardiovascular diseases throughout their lives,” the researchers said. “This may be due to the long-term use of chemotherapeutics, which has dose-dependent cardiotoxicity, leading to cardiomyopathy and heart failure.” [J Urol 2014;191:48-53]

Of note, this elevated risk of death is known to persist throughout cancer treatment and even up until late follow-up, they added. Due to this, a management approach that only reacts once clinical manifestations arise may not be optimal. “We advocate a proactive approach, which begins before any cancer treatment is given and lasts for a lifetime thereafter,” the researchers said.